'Invisible' Acrylic Bonding

[simonsk]

Can anybody help with the following problem:

We are working on a project that consists of an acrylic bonded panel (similar to a double glazed window) that has circular discs randomly placed within the 'sandwich' and bonded to both sides of the sandwich.

We are struggling to get a visually acceptable bond on the discs. If we put too much glue on then it seeps out from the edge of the disc, if we put too little then it is even more visible (when the sandwich is filled with water).

We need to bond both sides of the discs to provide structural strength.

Is there any kind of adhesive that will not creep? Maybe some kind of contact adhesive that can be applied to one surface only (the disc), which then dries before application??


Any help would be greatly appreciated!

 

[insideman]

Try ethylene dichloride. This is a solvent, not a stickum. All residue evaporates. It is widely used for cementing acrylics.

 

[Demon3]

Just to explain. The solvent dissolves the PMMA which then acts as it's own glue (solvent welding).

It's a good solution. Also vibrational welding will give adhesion without glue.

Clear silicone glue could work too where you can peel off any overage once cured.

Chris DeArmitt

http://www.phantomplastics.com

Consulting to the plastics industry

 

[MacGyverS2000]

You will also need to experiment with the proper amount of glue (and application pattern, if the disks are big) on each disk. When the proper amount is applied and in the proper spots, laying the top sheet on will result in no air bubbles and no squeeze-out.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[cpretty]

Another solvent commonly used for this task is methylene chloride.

The trick to getting a good bond is capillary action. Don't brush it on then stick. Just lay the parts together, then inject or brush the solvent into the joint. It will wick right across the joint if it isn't too large.

Another trick I have heard of to elimanate bubbles while doing this is to add acetic acid (vinegar). Haven't tried it myself so you will have to experiment with concentration etc to see if it works.

Another thought would be to use transfer tape. If label manufacturers can make windows in overlays that are stuck down and clear, then I am sure they will work for you. Try 3M 468 MP.

 

[MacGyverS2000]

The trick to getting a good bond is capillary action. Don't brush it on then stick. Just lay the parts together, then inject or brush the solvent into the joint. It will wick right across the joint if it isn't too large.

Tough to inject if the discs are in the middle of the plate, especially if the space between plates is thin.

Another trick I have heard of to elimanate bubbles while doing this is to add acetic acid (vinegar). Haven't tried it myself so you will have to experiment with concentration etc to see if it works.

Acetic acid can cause fogging of acrylics, particularly if there was any heating involved in the cutting (such as when cut by a laser).

Another thought would be to use transfer tape. If label manufacturers can make windows in overlays that are stuck down and clear, then I am sure they will work for you. Try 3M 468 MP.

The edges probably wouldn't look as crystal clear as the center, even if the center was...

Dan - Owner

http://www.Hi-TecDesigns.com